I've worked in the woods on
I've worked in the woods on the east coast and in the Pacific Northwest.
Poison ivy is hard to prevent. You could stay out of weedy or woody areas or wear pants. It's not the deep woods so much as younger, more recently disturbed forests. Haven't tried "Ivy Block".
However, if you get poison ivy, a product called TecNu is very good at limiting the damage.
Mosquitos are more manageable. DEET repellent does work, mostly. But if you prefer a more naturalistic approach, remember they reproduce in still water, so you want to stay to drier areas if you can. Most can't handle the wind so if you are in a windy place that helps a ton.
All in all it'd be a good time to stay out in the open -- like on ridgelines, meadows, well-kept fields, etc. Probably time to stay out of the woods, where there will be more water and not much wind.
Though of course you can always create a kind of wind by running as fast as you can!